Title

Regulation Of The Atpase Activity Of Abce1 From Pyrococcus Abyssi By Fe-S Cluster Status And Mg2+: Implication For Ribosomal Function

Keywords

ABCE1; ATPase; Fe-S cluster; PabABCE1; Ribosome

Abstract

Ribosomal function is dependent on multiple proteins. The ABCE1 ATPase, a unique ABC superfamily member that bears two Fe4S4 clusters, is crucial for ribosomal biogenesis and recycling. Here, the ATPase activity of the Pyrococcus abyssi ABCE1 (PabABCE1) was studied using both apo- (without reconstituted Fe-S clusters) and holo- (with full complement of Fe-S clusters reconstituted post-purification) forms, and is shown to be jointly regulated by the status of Fe-S clusters and Mg2+. Typically ATPases require Mg2+, as is true for PabABCE1, but Mg2+ also acts as a negative allosteric effector that modulates ATP affinity of PabABCE1. Physiological [Mg2+] inhibits the PabABCE1 ATPase (Ki of ∼1 μM) for both apo- and holo-PabABCE1. Comparative kinetic analysis of Mg2+ inhibition shows differences in degree of allosteric regulation between the apo- and holo-PabABCE1 where the apparent ATP Km of apo-PabABCE1 increases >30-fold from ∼30 μM to over 1 mM with Mg 2+. This effect would significantly convert the ATPase activity of PabABCE1 from being independent of cellular energy charge () to being dependent on with cellular [Mg2+]. These findings uncover intricate overlapping effects by both [Mg2+] and the status of Fe-S clusters that regulate ABCE1's ATPase activity with implications to ribosomal function. © 2012 Elsevier Ltd. All rights reserved.

Publication Date

8-15-2012

Publication Title

Archives of Biochemistry and Biophysics

Volume

524

Issue

2

Number of Pages

114-122

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.abb.2012.05.004

Socpus ID

84863611083 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84863611083

This document is currently not available here.

Share

COinS